Effect on platelet adhesion

It is desirable to find a simple surface property that will induce an equally simple and hence predictable behavior of plasma and its proteins and then of blood and its platelets. Are simple guidelines for building non-thrombogenic materials available or even possible Wettability (96), flow (97, 98y 99,100), and the effects of air/liquid interfaces (101) all seem to be relatively simple, physical factors with a clear effect on platelet adhesion. Physical, hydrophobic bonding, e.g., a force imposed... 

Atromld S reduces platelet adhesiveness and increases bleeding time in man. Estriol, in man, has no effect on platelet adhesion. ... 

Our original interest in this area was prompted by the fact that red cells are a major component of blood and as such might have some effect on protein adsorption. In addition we had shown (58) that red cells have a strong augmenting effect on platelet adhesion probably due to the increased mixing action deriving from red cell local motions in flowing blood. Similar effects of red cells on platelet diffusion have been noted by others (59). 

Heparinization, as is seen from Table 12, results not only in the increase in blood clotting time, but also in an increase of the platelet adhesion the increase in both cases being more intensive the higher the content of the immobilized heparin. It should be noted that there is a complete agreement between the scientists concerning the effect of heparin on the blood clotting time the result of the contact of blood with HCP is considered analogous to that of the direct injection of soluble heparin into the bloodstream, whereas the data on platelet adhesion is quite contradictory. 

The diversions concerning the effect of heparin on platelet adhesion may probably be attributed to the different binding strengths of heparin to the polymer. When heparin is, at least to some extent, leaking into the bloodstream, the platelet adhesion... 

Fig. 13. Effect of water content of hydrogels on platelet adhesion PVA ( ),PAAm (O),methoxy-PEG methacrylate (A), PVP ( ), and PEG (A)...

Because the endothelium has important inhibitory effects on platelet aggregation, monocyte adhesion, and smooth muscle cell (SMC) proliferation, strategies to improve vascular healing after spontaneous or induced injury may improve clinical outcomes in the long-term (Fig. I). 

Dr. David Calverley is a hematologist with a research interest in the molecular mechanisms of platelet adhesion and activation. His clinical interest lies in the area ofplatelet and hemostatic disorders. In addition to research, clinical, and teaching activities, he is Associate Director of the University of Southern Califomia/Nonis Cancer Hospital Qinical Coagulation Laboratoiy. Dr. Gerald Roth is a hematologist with interests in both research and clinical aspects of platelets. He has studied molecular aspects of aspirin s effect on platelets and observed the acetylation reaction between aspirin and platelet cyclo-oxygenase. 

Literature on the effects of dextran on platelet adhesiveness is contradictory. The method of measurement is important. It appears to... 

Cell adhesion Nitric oxide has effects on cell adhesion that result in redueed platelet aggregation and reduced neutrophil adhesion to vaseular endothelium. The latter effeet is probably due to reduced expression of adhesion moleeules by endothelial cells. 

Fibrinogen is one of the proteins to be considered as vulnerable to alteration when adsorbed at the interphase between blood and an air nucleus (15-16). To examine this possibility, we have conducted two series of experiments. In the first, we examined the amount of fibrinogen that is adsorbed on normally primed silicone rubber and the amount adsorbed on the same type of material after it has been primed so as to remove the gas nuclei (IL i )> in the second series of experiments, the effect of preadsorbed fibrinogen on platelet adhesion was examined. 

Bryan GC, Scudder J (1952) Dextran and pneumococcus polysaccharide cross-reactivity in skin tests and serum precipitin tests. Ann NY Acad Sci 55 477-478 Bygdeman S, Eliasson R (1967) Effect of dextrans on platelet adhesiveness and aggregation. Scand J Clin Lab Invest 20 17-23... 

The majority of hemocompatibility studies are performed under static conditions, but some groups considered the effect of flow on platelet adhesion in dynamic experiments. As one example, randomly structured PMMA surfaces with feature sizes of 40 nm, 80 nm, and 400 nm and heights of 3nm, 13 nm, and 50 nm were investigated under flow conditions [108,109], Experiments with human whole blood showed a preferred adsorption of vWF compared to that of fibrinogen and albumin, which is in conflict with other static studies. It is apparent that different adsorption behaviors of plasma proteins can be observed under different flow conditions. The platelet adhesion was highest on those samples with the most vWF adhesion, namely the larger structures. Experiments were carried out with washed platelets and revealed other results. Platelets preferred the smaller structured surfaces for adhesion, which shows the severe influence of blood cells and plasma proteins on the adhesion behavior of platelets [108]. 

Ding Y, Leng Y, Huang N, Yang P, Lu X, Ge X, et al. Effects of microtopographic patterns on platelet adhesion and activation on titanium oxide surfaces. J Biomed Mater Res A March 2013 101(3) 622-32. 

Koh LB, Rodriguez I, Venkatraman SS. The effect of topography of polymer surfaces on platelet adhesion. Biomaterials 2010 31(7) 1533-45. 

Bordia, A., and Verma, 8. K., 1985, Effect of vitamin C on platelet adhesiveness and platelet aggregation in coronary artery disease patients, Clin. Cardiol. 8 552-554. 

Derivatives of l,3-bis-[6,7-dimethoxy-3,4-dihydroisoquinoline-(l))-2-arylpropane reduce platelet adhesiveness, aggregation, retraction and liberation of biogenic amines from cells in idiich these CMqpounds have accumulated Derivatives of 3-alkyl-3-carbalkoxy-6,7-dimethoxy-3,4 dihydro-isoquinolines also have the same effect on platelets ... 

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